Memory devices can be categorized in two broad areas: volatile and non-volatile. Volatile memory devices require power to maintain data, while non-volatile memories are capable of maintaining data in the absence of a power supply. An example of a non-volatile memory is the flash memory that stores information in a semiconductor device without the need for power to maintain the information in the chip.
Flash memory can be built using either NOR or NAND devices. NAND flash can be either of single-level cell (SLC) or multi-level cell (MLC) configuration. MLC NAND flash allows for a higher density memory device in comparison to SLC NAND flash because it allows the storage of two or more data bits in each memory cell.
A trend in the design of memory devices, including flash memory, is to decrease the size of the memory device. One way of achieving this reduction in size is to reduce the size of the features that comprise the memory device. The reduction in the size of features induces a reduction in the size of devices included in the memory device, including the interconnective lines or traces used to electrically couple the circuit within the memory device. The reduction in the size of features also may include a reduction in the size of spaces between one or more features in the memory device, including but not limited to a reduction in one or more spaces between interconnective lines in the memory device. As a result, the techniques used to form the memory devices must increasingly be capable of producing smaller and more closely spaced components that comprise these memory devices.